Research on Dead Time of Half-Bridge LLC Resonant Circuit Based on SiC MOSFET

As the third generation semiconductor with wide band gap, SiC MOSFET not only has fast switching speed and better switching characteristics, but also has certain efficiency in the converter. LLC resonant converter has been widely concerned as an efficient DC-DC converter. SiC MOSFET is used as the primary side switch of half-bridge LLC resonant converter to further improve the efficiency of the converter. Zero voltage switching can reduce the loss and improve the efficiency of half-bridge LLC resonant converter. This paper analyzes the influence of dead time on zero voltage turn-on, and calculates the critical dead time. The switching performance of SiC MOSFET was tested by setting up a dual-pulse experimental platform. By setting up a half-bridge LLC resonant converter, different dead time was set for comparative experiments. The experimental results show that the dead time is too large to achieve zero voltage switching.